Congenital pulmonary lymphangiectasia
Description, Causes and Risk Factors:
Congenital pulmonary lymphangiectasia is a rare developmental disorder that is present at birth (congenital). Affected infants have abnormally dilated lymphatic vessels within the lungs. The lymphatic system helps the immune system in protecting the body against infection and disease. It consists of a network of tubular channels (lymph vessels) that drain a thin watery fluid known as lymph from different areas of the body into the bloodstream. Lymph accumulates in the tiny spaces between tissue cells and contains proteins, fats, and certain white blood cells known as lymphocytes.
CPL can occur as a primary or secondary disorder. Primary pulmonary lymphangiectasia can occur as isolated congenital defect within the lungs or as part of a generalized form of lymphatic vessel malformation (lymphangiectasia) that affects the entire body. Secondary Congenital pulmonary lymphangiectasia occurs secondary to a variety of heart (cardiac) abnormalities.
The exact cause of CPL is not known. It has been suggested that Congenital pulmonary lymphangiectasia lymphatic channels of the fetal lung do not undergo the normal regression process at 20 weeks gestation, and thus large lymphatic vessels persist, that are normal in the 9-16 week gestation maturation development process. Obstruction of pulmonary lymphatics or veins, or the action of infectious agents have also been taken into consideration.
Secondary Congenital pulmonary lymphangiectasia may be caused by a cardiac lesion. Pulmonary lymphatics dilatation develops in utero because of obstructed pulmonary venous flow, or it can be caused by cardiac lesions which has been hypothesized to interfere with the normal regression of the lymphatic tissue elements after the 16th week of fetal life.
The incidence of Congenital pulmonary lymphangiectasia is not clearly defined. Any attempt to provide precise statistics regarding the incidence of CPL would be misleading considering that to date only a few isolated cases or small series have been reported. Congenital pulmonary lymphangiectasia may be associated with non-immune hydrops fetalis and with congenital chylothorax. Although the incidence of these conditions is not directly correlated to the possible incidence of CPL, it may be useful to keep in mind that the incidence of hydrops fetalis in obstetric-neonatal referral centers may be as high as 1:800. Furthermore, this condition carries a poor prognosis with a mortality rate ranging from 50% to 98%, and the incidence of congenital chylothorax is about 1:10,000-15,000 pregnancies, with a male-female ratio of 2:1.
Infants with CPL often develop severe, potentially life-threatening, respiratory distress shortly after birth. Affected infants may also develop cyanosis, a condition marked by abnormal bluish discoloration of the skin that occurs because of low levels of circulating oxygen in the blood.
The diagnostic approach includes the following: complete family and obstetric history, ultrasound examination and magnetic resonance studies searching for twin gestation, anatomic abnormalities, heart fetal echo, and Doppler blood flow assessment, maternal evaluation including blood type, Rh (Rhesus), antibody screening, Kleihauer-Betke stain, Toxoplasma gondii, Rubella virus, Cytomegalovirus, herpes simplex virus, Enterovirus, syphilis, chickenpox
virus, varicella zoster virus, Lyme disease
, Borrelia burgdorferi, AIDS, parvovirus B19, metabolic studies, and Hb electrophoresis, invasive fetal assessment including amniocentesis and fetal effusion sampling.
The postnatal diagnostic approach includes the laboratory and instrumental evaluation that is needed to rule out various conditions possibly related to Congenital pulmonary lymphangiectasia and to establish whether CPL is primitive or secondary.
Hematologic causes can be ruled out by blood cell count, Kleihauer-Betke stain, Hb electrophoresis, CBC and smear, cardiovascular causes can be excluded by echocardiogram and ECG, genitourinary causes by kidney sonography, Bun and plasma-urine creatinine, chromosomal syndromic, and metabolic disease by usual diagnostic protocols.
Other tests may include: Conventional radiologic studies, CT scans, MRI scans, lymphoscintigraphy, lung biopsy, bronchoscopy, and pleural effusion examination.Chest x-ray usually show hyperinflation with interstitial markings.Obstetric fetal ultrasound evaluation plays a key role in the antenatal diagnosis of CPL.
Treatment is generally supportive. At birth, in the presence of severe respiratory distress associated with pleural effusion, delivery room management could be a challenge and multiple procedures might be required. Tracheal intubation and assisted ventilation are usually necessary. When effective gas exchange is not reached, sterile thoracentesis and/or paracentesis must be taken into consideration. Fluid replacement, inotropic support, and in case of persistent pulmonary hypertension, ventilatory management with high frequency oscillatory ventilation and/or nitric oxide may be necessary. Airway, chest wall, and pulmonary edema, pleural effusion, pulmonary hypoplasia with associated respiratory distress syndrome, perinatal depression, hypoxia, and acidosis are the main problems that occur during delivery room resuscitation and then during at birth stabilization.
The immediate at birth evacuation of the pleural effusion with assisted ventilation may lead to favorable outcome of respiratory distress. Respiratory problems that occur in the post-neonatal age, and that can continue over the next years of life often need home supplemental oxygen and symptomatic treatment for recurrent cough and wheeze. A great deal of attention must be paid to avoid bronchitis since common respiratory pathogens are usually involved. Cultures from bronchoalveolar lavage should be done in order to start selective antibiotic treatment.
In patients with rapidly expanding pleural effusion that requires placing unilateral or bilateral chest tubes, the large amount of fluid that is drained over days and weeks lead to the loss of great quantities of albumin, and many other plasma factors that must be replaced, in some cases even on a daily basis. Gastroesophageal reflux requires standard treatment.
Nutrition plays an important role in reducing lymphatic production. Enteral nutrition with medium chain triglycerides and total parenteral nutrition were successfully employed. Octreotide and antiplasmin have been used in Congenital pulmonary lymphangiectasia and in intestinal lymphangiectasia.
When the chyle leakage persists, pleurodesis by instillation of sclerosing agents or parietal pleurectomy appear to be effective. Pleurodesis may be associated to thoracic duct ligation or suture of leaking collaterals.
NOTE: The above information is educational purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.